In certain types of equipment, such as compactors, log splitters, dock levelers, and the like, it is desirable for a hydraulic cylinder to operate in a programmed sequence, in which the piston rod is extended and then immediately retracted without operator action. To accomplish this sequencing, the cylinder unit normally includes limit switches, sensors, or complex valving, which substantially increases the overall cost of the unit.
Therefore, there has been a need for a simple and inexpensive mechanism for automatically sequencing a hydraulic cylinder and which may be retro-fitted to existing cylinders.